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  • #16
    Re: Slowing down the roast

    Usually people add beans when using a chimney to lengthen the roast time.

    Java "Questioning look" phile
    Toys! I must have new toys!!!

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    • #17
      Re: Slowing down the roast

      Originally posted by Javaphile link=1118894468/15#15 date=1119194527
      Usually people add beans when using a chimney to lengthen the roast time.

      Java "Questioning look" phile
      Opinion seems to be split on this with some saying less beans = longer roast and others saying more beans = longer roast time. It seemed to me that less beans roasted both longer and more evenly, although it may be that 100g green is the max that my popper can handel, so constitutes the more beans. Will have to experiment.

      How high to people fill the popper with chimney - eg to the top of the roasting chamber in the popper?

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      • #18
        Re: Slowing down the roast

        It depends on the size/height of the chimmney. I use a Tin can and put a cup of beans in, otherwise they start getting chucked out the top.

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        • #19
          Re: Slowing down the roast

          Hi All,

          Regarding controlling Roast Temp in a popper, you definitely have to ADD beans to INCREASE the Roast Temp, and REMOVE beans to DECREASE the Roast Temp.

          This info was gathered via experiment using a Fluke DMM with K type Thermocouple, with the t/c bead situated so that it was roughly half-way up the bean roasting column. Increased temperature translates to shorter roast times and visa-versa.

          Eventually you reach a point where the Fluid Bed collapses due to overloading the roast batch size. Obviously you need to stop adding beans well before this point to avoid burning both your beans and melting your popper. Hope this helps,

          Cheers,
          Mal.

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          • #20
            Re: Slowing down the roast

            Ive worked out a fool proof way to slow the roast: shelve the popper and buy a heat gun.

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            • #21
              Re: Slowing down the roast

              Uhh Yeah,

              Great solution but what about those of us who cant use a Heat Gun or any other hand held device? In my situation for example, after a series of strokes I have very limited strength and dexterity in my left arm and hand, and about a third left in my right. Makes trying to wield a Heat Gun or similar very difficult....

              Cheers,
              Mal.

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              • #22
                Re: Slowing down the roast

                Just tie the heatgun up with some string so its hanging over the beans. I suspend mine between the bbq and the balcony railing. That way you can adjust the roast timing by varying the distance the gun is from the beans (by removing heat pads from under the colander).

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                • #23
                  Re: Slowing down the roast

                  Hmmm,

                  Still doesnt sound as easy as using my popper. Just plug it in, pour in the beans, turn it on, turn it off, pour beans into fan cooler. Im not too good at trying to tie things up with string and getting the angle of the dangle, just so.

                  My ultimate aim is to build a modified Stir Crazy/Turbo Oven roaster so that I can reduce the number of roast batches that I currently do. In the end, I guess we all use a method that works best for each individuals situation. The $50 ALDI Turbo Oven has me very interested at the moment.

                  Cheers,
                  Mal.

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                  • #24
                    Re: Slowing down the roast

                    They have them at coles to for $59???

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                    • #25
                      Re: Slowing down the roast

                      Mal

                      The most I could stretch my popper out to was 7 minutes, outside with 100g of beans on a 7 deg night. Summer is a no-go zone with my popper. If you could get your popper over 7 minutes regularly then the heat gun is probably not an issue - unless you need to roast a lot of coffee and are time poor. With all these issues the heat gun was a saviour for me.

                      If I could get the stir crazy turbo thing happening then thatd be even better but my mother in law wont give me her turbo with glass lid.

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                      • #26
                        Re: Slowing down the roast

                        Originally posted by AlMac link=1118894468/15#24 date=1120184210
                        If I could get the stir crazy turbo thing happening then thatd be even better but my mother in law wont give me her turbo with glass lid.
                        Ohhh,

                        What a spoiled sport. Cant you bribe her with promises of unbelievably great coffee? Or is she a non-imbiber?

                        Re: my popper... I have made a small mod that allows me to control the fan speed and therefore the roast size and duration. We probably only go through about 280-400 grams of coffee per week, depending on visitors and relies, etc so the popper is well up to the job being asked of it at this stage.

                        Cant help thinking that a good SC/TO roaster would be a considerable step up though.... now where did I put my tinkering cap, got so many of the damn things these days I keep losing em. All the best,

                        Mal.

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                        • #27
                          Re: Slowing down the roast

                          I have had the same experience. I can tell you that there arent many solutions. A popper in a warm environment will need serious modification to the way it ventilates and allows air to the element and really modification to the thermostat.
                          For a cheap popper none of ths is feasable.
                          If you have a good quality popper like the poppery, you can do it but all the cheap stuff is just too crappy. If you dont mind sacrificing your popper then it would be worth trying to mod it, there are plenty of web sites out there that willtell you how.
                          Sorry to bring you bad news but its not a brick wall, dont give up.
                          Sacrifice your popper to science and play around with it.
                          Cheers...
                          Bruce...

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                          • #28
                            Re: Slowing down the roast

                            Originally posted by Bruce link=1118894468/15#26 date=1120286092
                            I have had the same experience. I can tell you that there arent many solutions. A popper in a warm environment will need serious modification to the way it ventilates and allows air to the element and really modification to the thermostat.
                            For a cheap popper none of ths is feasable.
                            Cheers...
                            Bruce...
                            Hi Bruce,

                            I spose it all comes down to what you call a serious mod and what you interpret as feasible. Ive got two Mistral poppers and at $17.00 each, I guess they would have to fall in to the "cheap" category.

                            In order to improve the amount of air being transported through the roasting chamber, I have made two relatively simple mods (one on each popper) that differ slightly from each other but achieve more or less the same outcome. I would always recommend that anyone contemplating a modification to an Electrical Appliance, should enlist the assistance of a friendly local licensed electrician. Its not that the mods are complex but its better to be safe than sorry where 240 Volts is concerned.

                            The simplest of the two mods involved a procedure to reduce the resistance of the Fan Motor Dropping Resistor and thereby increase the Voltage to the Motor.... more Voltage equates to more speed. This mod took about 30 minutes to complete using only basic tools and materials.

                            The second mod went a bit further in that a Fan Motor Speed Control was devised and fitted. A little more complex than the first but not overly so. This involved the use of more materials and components, and therefore cost too but in all, everything was purchased for less than $20.00 all up and took about 2 Hours to complete... still not excessive in my opinion.

                            As things turned out, I didnt have to touch the t/stats or the fusible link and left these "as is" and in circuit to provide a level of over temperature protection. Using a Fluke DMM with a Fluke K type t/couple temperature probe, I measured the temp in the roasting chamber of each popper during a roast, about midway of the vertical column of beans.

                            The popper with the basic mod starts off at around 195 C once the fluid bed is established and ramps up slowly to about 218 C before the onset of 2nd Crack. The popper with the variable speed fan is a lot more flexible in that I can roast larger batches, stretch the roast out or contract it, basically whatever I want within the limits of the fans safe operating limits. Currently, this is set to a maximum of 20% above the nominal Fan Motor Voltage of 25 Volts D.C. which so far, hasnt been to the detriment of the Fan or Motor. In practice, I have never had to exceed 10-12% above nominal applied voltage in order to stretch roast batches of 120 grams out to 12-13 minutes in the middle of Summer.

                            Since I dont have an Air Flow-meter, it is impossible therefore to accurately estimate the actual volumes of air being transported through the popper but at plus 10%, the increase in air flow is very noticeable as an increase in force against my hand. I suppose I could rig up a water column Manometer and measure the changes in Static Air Pressure but even for me, this would probably be going a bit too far. It is after all, only intended as a basic mod to allow me to derive a basic level of control over my roasts for the least amount of expense, in terms of both money and effort.

                            So, for my money, the "cheap" popper is definitely the way to go. Why risk damaging a more expensive unit, even without the mods, to the extra hardship of roasting coffee? Regarding feasibility of such an undertaking. I believe it is entirely feasible providing the usual precautions are taken when playing with the innards of a 240 Volt appliance. Theres bound to be a Sparky not too far away from most Roasters who would be only too happy to help out when some top quality coffee may be offered in return.

                            I guess when you come right down to it, yes, I am a tinkerer but so are a great many CS members. Its kind of a second nature to most of us and for those less imbued with this kind of enthusiasm, there are enough keen members out there to help others out when and if the opportunities arise and practicalities allow. I sure dont mind helping out wherever I can. Anyway, time for bed so, all the best and

                            Cheers,
                            Mal.

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                            • #29
                              Re: Slowing down the roast

                              Originally posted by Mal link=1118894468/15#25 date=1120273331

                              Ohhh,

                              What a spoiled sport. Cant you bribe her with promises of unbelievably great coffee? Or is she a non-imbiber?
                              Already did that - she no longer drinks Nescaf - just flat whites at our house.

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                              • #30
                                Re: Slowing down the roast

                                My "cheap" solution to Variac is to use 2 dimmers set up in parallel.
                                Since my popper is rated at 1200W, and the dimmer are 600W, putting them in parallel distributes the load.
                                But that means, you have to adjust the knobs together. To aid that, i mounted my two dimmers on a box side by side and wrapped a big rubber band across the two knobs.
                                With the separate fan control it works really great!
                                Kai Seng

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